diff --git a/README.md b/README.md
index 4dd158e..2aea55f 100644
--- a/README.md
+++ b/README.md
@@ -1,8 +1,7 @@
 # evolved.lua (work in progress)
 
 ```
-id :: id
-alive :: id -> boolean
+id :: integer? -> id...
 
 pack :: integer, integer -> id
 unpack :: id -> integer, integer
@@ -10,6 +9,9 @@ unpack :: id -> integer, integer
 defer :: boolean
 commit :: boolean
 
+alive :: entity -> boolean
+empty :: entity -> boolean
+
 get :: entity, fragment...  -> component...
 has :: entity, fragment -> boolean
 has_all :: entity, fragment... -> boolean
diff --git a/ROADMAP.md b/ROADMAP.md
index d737261..0014cc3 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -6,3 +6,4 @@
 - should insert/assign throw errors on failure?
 - add auto chunk count reducing
 - batching api for set/assign/insert/remove/clear/destroy
+- every chunk can hold has_on_assign/has_on_insert/has_on_remove tags
diff --git a/develop/untests.lua b/develop/untests.lua
index f0f0cdf..6ed9a3e 100644
--- a/develop/untests.lua
+++ b/develop/untests.lua
@@ -552,6 +552,32 @@ do
     assert(not evo.alive(e))
 end
 
+do
+    local f = evo.id()
+
+    do
+        local e = evo.id()
+        assert(evo.empty(e))
+
+        evo.insert(e, f, 42)
+        assert(not evo.empty(e))
+
+        evo.clear(e)
+        assert(evo.empty(e))
+    end
+
+    do
+        local e = evo.id()
+        assert(evo.empty(e))
+
+        evo.insert(e, f, 42)
+        assert(not evo.empty(e))
+
+        evo.destroy(e)
+        assert(evo.empty(e))
+    end
+end
+
 do
     local f1, f2, f3 = evo.id(3)
 
diff --git a/evolved.lua b/evolved.lua
index a11700b..408154f 100644
--- a/evolved.lua
+++ b/evolved.lua
@@ -1009,13 +1009,6 @@ function evolved.id(count)
     end
 end
 
----@param id evolved.id
----@return boolean
----@nodiscard
-function evolved.alive(id)
-    return __alive_id(id)
-end
-
 ---@param index integer
 ---@param version integer
 ---@return evolved.id
@@ -1042,6 +1035,21 @@ function evolved.commit()
     return __defer_commit()
 end
 
+---@param entity evolved.entity
+---@return boolean
+---@nodiscard
+function evolved.alive(entity)
+    return __alive_id(entity)
+end
+
+---@param entity evolved.entity
+---@return boolean
+---@nodiscard
+function evolved.empty(entity)
+    return not __alive_id(entity)
+        or not __entity_chunks[__unpack_id(entity)]
+end
+
 ---@param entity evolved.entity
 ---@param ... evolved.fragment fragments
 ---@return evolved.component ... components